A miniaturized, portable and automatic air-traffic control (ATC) system to determine the position of air vehicles is described. The system is composed by a portable control tower that detects manned air traffic equipped with ADS-B or transponder, and a computer compatible software to display the position of the detected air vehicles. This system is used in conjunction with a drone system, providing to the latter the air-traffic local information. The information given to the drone system allows performing automatic collision avoidance with the air vehicles detected in the flight area of the drone.